1. Field of the Invention
The present invention relates to a method for creating lifelike images for computer deformed objects, and more particularly to a method to imitate lifelike images, which uses a statistical regression analysis method to create a weighted value table that is used to estimate positions of desired specific points on the deformed object or robotic face.
2. Description of Related Art
Computer deformed objects and animated facial expressions of robots need to be lifelike so that the deformed objects look real. Methods for imitating and creating lifelike images for computer deformed objects in accordance with prior art can be found in U.S. patents by Kelly Dillon, U.S. Pat. No. 6,020,892, Christian Rouet etc, U.S. Pat. No. 5,818,461, Pierre LaChapelle, U.S. Pat. No. 6,163,322, Erich Haratsch, et. al., U.S. Pat. No. 6,483,513 B1, Eric Cosatto, et. al.,. U.S. Pat. No. 5,995,119, Tsutomu Ando, U.S. Pat. No. 6,476,815 B1 and Volker Blanz, et. al., U.S. Pat. No. 6,556,196 B1.
The conventional methods for creating lifelike images in the aforementioned patent documents typically use either interpolation or image composition methods to imitate animated images and can be divided into the following categories.
The first conventional method prepares many images of different shapes or expressions by deforming a physical object before animating an object. The prepared images are stored in a database, and the images will occupy a huge storage space in the database. Therefore, the first method to animate an object requires observation of changes in the shape of a similar physical object and identifying stored images for an image that that are close to a recent image of the physical object as the physical object becomes deformed.
The second conventional method uses interpolation to calculate positions of some desired points on imitated lifelike images to create the animated images of the physical object. The images of the physical object must be observed before and after the physical object changes, and then using an interpolation method, the desired points on the animated images are calculated. Such a method is included in the 3DS MAX software uses a morphing function to embody the animated images.
The third conventional method is similar to the first method, but the third method uses a method of calculating proportional differences between the different representative images to form lifelike composites of the animated images of the deformed objects.
The fourth conventional method determines several measurable points and specific points on the physical object's surface, and then establishes a weighted value table by calculating distance differences between each of the specific points to all the measurable points. When the physical object's appearance or shape has changed, the displacements of all the measurable points are measured, and the positions of the specific points can be found by a relationship related to the displacement of the measured measurable points and the weighted value table. Thereafter, the deformations can be created since the positions of all the measurable points and the specific points are known after the physical object has changed shape. This method is included in the MAYA and 3DS MAX software.
However, the first and the second conventional methods require a huge database to store the pre-processed images and can only imitate an image that was created and stored in the database prior to the animation. If a desired image cannot be found in the database, the desired animated image cannot be created. Furthermore, the time required to search the entire database for a stored image with the two methods makes real-time animation prohibitive.
The third conventional method also requires a huge database to store representative images for image composition. The application of the third conventional method is limited by the quantity of representative images stored in the database. Although, an improvement called Principal Component Analysis (PCA) has been incorporated in the third conventional method to reduce the storage space required in the database for the representative images. However, PCA necessitates a great deal of pre-processing, which takes time.
The fourth conventional method requires a specialist, such as a professional animator, to create the weighted value table based on the physical features of the object, such as muscle distribution of a body. Creating the weighted value table is a huge task and is particularly difficult if the physical features of the object cannot be clearly distinguished or found.
To overcome the shortcomings, the present invention provides a method to imitate living images in real-time for computer deformation of objects in real-time to mitigate or obviate the aforementioned problems.